Acoustic attenuation materials are used in a wide variety of applications where it is desired to attenuate acoustic signals. Acoustic attenuation material may be used, for example, in soundproofing materials used in architectural applications. Many such acoustic attenuation materials require considerable volume to achieve desired levels of attenuation.
Acoustic attenuation materials are also incorporated into relatively small devices where control of acoustic energy is required. One such application is in the field of ultrasound imaging probes. Ultrasound imaging probes continue to enjoy widespread use in the medical field. By way of example, ultrasound probes are utilized for a wide variety of external, laparoscopic, endoscopic and intravascular imaging applications. The ultrasound images provided by imaging probes may, for example, be used for diagnostic purposes.
Ultrasound imaging probes typically include a plurality of parallel piezoelectric transducer elements arranged along a longitudinal axis, with each element interconnected to a pair of electrodes. Typically, the transducers are subdivided in the longitudinal direction by dicing during production, resulting in independent transducer elements that enable electronic steering and focusing within an imaging plane. An electronic circuit, interconnected to the electrodes, excites the transducer elements causing them to emit ultrasonic energy. The transducer elements may be operable to convert received ultrasonic energy into electrical signals, which may then be processed and used to generate images.
Typically, the transducers include an active layer of a piezoelectric material with an acoustic face from which acoustic signals are emitted. Often an acoustic damping member is disposed rearward of the active layer on an opposite side of the active layer from the acoustic face. The acoustic damping member serves to damp undesirable acoustic signals (e.g., signals that may emanate from and be reflected back to the rear face of the transducer) that may interfere with the acoustic signals received at the acoustic face. As may be appreciated, for a particular acoustic damping material, acoustic damping capabilities typically increase as the volume of the acoustic damping member increases. Accordingly, as the acoustic damping member is reduced in volume, the acoustic damping capabilities typically decrease. Consequently, the overall volume and mass of an ultrasound probe that includes an ultrasonic transducer and acoustic damping member may be at least partially dependent on the acoustic damping capabilities of the material of the acoustic damping member.